The present invention relates generally to the field of metal castings, and in its most preferred embodiments to the field of methods and systems for manufacturing hollow metal castings.
Methods and apparatus for manufacturing hollow metal castings such as, for example, cylinder heads and engine blocks, are well known. Conventionally, multiple discrete methods and apparatus are employed in the manufacture of metal castings. For example, in accordance with one conventional method, a core machine is employed to manufacture cores and molds from sand and a combustible binder. At a casting machine that is remote from the core machine, molten metal is poured into a mold with a core properly disposed therein. Then, the core and mold are removed from the newly formed casting at a "shake-out" machine by forcibly shaking the newly formed casting and breaking the core and mold away therefrom. At a location remote from the "shake-out" machine, sand is reclaimed from the broken cores and molds in a reclaiming machine. After "shake-out", and at a location remote from the "shake-out" machine, the newly formed castings are introduced into a heat treating furnace for heat treatment. Because each of the above steps are conventionally carried out by discrete pieces of equipment, capital equipment costs, floor space requirements, and operating costs are typically not maximized.
Revolutionary improvements have recently been made to minimize capital equipment costs, floor space requirements, and operating costs. The revolutionary improvements are embodied in a multifunctional furnace that eliminates and synergistically combines certain of the above-identified steps and the equipment therefore. The revolutionary improvements are fully disclosed in U.S. Pat. Nos. 5,354,038 and 3,294,094, each of which is expressly incorporated herein, it in its entirety, by reference. The improvements disclosed in those patents totally eliminate the need for any "shake-out" to remove cores and molds (referred to hereafter together as cores) from castings. The multifunctional furnace, in addition to heat treating, removes cores and molds from castings. The combustible binder that binds cores is combusted in the multifunctional furnace and differential pressure is established across the castings, whereby cores fall from castings while the castings are within the multifunctional furnace. The cores that fall from the castings actually fall in pieces, and the pieces of core are collected in hoppers within the multifunctional furnace. Sand is reclaimed from the pieces of core while within the hoppers, in part, by the action of fluidizers. While the inventions disclosed in the patents incorporated herein by reference have revolutionized the methods and apparatus for manufacturing hollow metal castings, room for inventive improvement still remains.
As discussed briefly above, cores are typically constructed in core machines where sand and a combustible binder are combined. Additionally, an inducing gas is typically injected into core machines to facilitate curing of the combustible binder. An excess amount of inducing gas is commonly supplied to facilitate the curing, and typically a large percentage of inducing gas escapes from the core machine into the workplace and surrounding environment. An acceptable inducing gas, and one that is commonly employed, is amine gas. The escape of amine gas from the core machine is thought to be a potential workplace and environmental hazard. An additional problem with respect to the formation of cores is that some of the combustible binder within core machines is often not cured and is therefor not solidified. Thus, there is a nonsolidified mixture of core materials (i.e., uncured scrap) which is a messy waste product that must, unfortunately, be contended with.
As mentioned above, after formation of cores and molds, cores are properly disposed within molds and molten casting material is poured into the molds while they are in a casting machine. The molten casting material is typically at a temperature that is above the combustion temperature of the binder material of the mold and core, whereby the mold and core smolder and emit noxious fumes that commonly escape from the casting machine to pose a potential workplace and environmental hazard.
Room for improvement additionally exits with respect to the improved multifunctional furnaces disclosed in the patents incorporated herein by reference. These multi functional furnaces have a tendency in certain circumstances to be higher than some older conventional furnaces due, in part, to their inventive incorporation of components not included in conventional furnaces. Thus, it can be difficult in some cases to physically fit the improved multifunctional furnaces into an older factory or building due to ceiling or roof clearance problems.